Patent GB-711376-A (GB)
Title: Improved process for preparing metal phthalocyanines
IPC: C09B47/06
Filed: 1951-10-25
Abstract: In a process for preparing a metal phthalocyanine which comprises heating at phthalocyanine-forming temperature, preferably 150 DEG -210 DEG C, a reaction mixture containing an organic phthalocyanine intermediate of the class consisting of aromatic ortho - dicarboxylic acids, their anhydrides acid halides, esters, salts, mono- and diamides, esters and ammonium salts of the monoamides, imides and iminoimidines, the corresponding orthocyanocarboxylic acids and their esters, amides and ammonium salts, and corresponding o ,o \sv-polyhalo-o-dimethyl and o -polyhalo-methyl-o-cyano aromatic compounds; a nitrogen donor consisting of urea, biuret, guanidine, guanidyl-urea, dicyandiamide, or cyanuric acid, and a phthalocyanine-forming metal yielding reagent in the presence of an inert organic liquid diluent and of a catalyst containing an element of Group V or VI of the Periodic Table and of atomic number 15 to 92, suitable for promoting phthalocyanine formation, there is included in the reaction mixture an amount not substantially less than 25 per cent of the weight of the said phthalocyanine intermediate, of a compound selected from the group consisting of sulphuric acid, sulphamic acid, alkyl monoesters of sulphuric acid derived from alcohols of 1 to 5 carbon atoms, alkali metal, alkaline earth metal-, ammonium-, and phthalocyanine-forming metal salts of the said acids and monoesters, sulphamide, and dialkyl sulphuric esters derived from alcohols of 1 to 5 carbon atoms.  The preferred organic phthalocyanine intermediates are of the benzene series and may contain additional nuclear substituents, e.g. halogen such as chlorine or bromine, nitro, alkyl, aryl, alkoxy, aryloxy, alkyl-thio or aryl-thio radicals and alkyl or aryl acyl groups.  The catalyst is preferably a molybdate such as alkali metal or ammonium molybdates, phosphomolybdates or tungsto-molybdates and is generally employed in amounts of from 0.1 to 2 per cent of the weight of the total reaction mixture. Suitable metal-yielding reagents are copper, aluminium, magnesium, nickel, iron, cobalt, tin, zinc, and vanadium, and their salts such as the halides, e.g. chlorides or bromides, sulphates, nitrates, and the oxides are also mentioned.  When the sulphate, sulphamate, or sulphuric ester salt of a phthalocyanine-forming metal is employed as promoter and also entirely or in part as the metal yielding reagent, the amount of salt based on the metal content thereof required to form the phthalocyanine is excluded or subtracted from the amount of said salt in calculating the amount acting as promoter.  Suitable solvents for the reaction are trichlorobenzene, dichlorobenzene, naphthalene and its chlorinated derivatives, quinoline, benzophenone, and nitrobenzene.  In examples: (1a) phthalic anhydride, urea, and aluminium chloride are reacted at 200 DEG -205 DEG C., in the presence of ammonium molybdate, anhydrous sodium sulphate and trichlorobenzene to yield chloroaluminium phthalocyanine; (1b) similar results are also obtained by using calcium, magnesium or aluminium sulphate instead of sodium sulphate; (2) as in (1a) except that phthalamide, phthalimide, or o-cyanobenzamide are used instead of phthalic anhydride and tetrachlorobenzene and trichlorobenzene are used as solvent; (3) copper hexadecachlorophthalocyanine is obtained by reacting tetrachloro-phthalic anhydride, urea and cuprous chloride in the presence of ammonium molybdate, sodium sulphate (ammonium sulphate or calcium sulphate), and trichloro benzene; (4) phthalic anhydride, urea, and anhydrous nickel chloride are reacted at 200 DEG C in the presence of amonium molybdate, anhydrous sodium sulphate (or ammonium sulphate) and tri-chlorobenzene as diluent to yield nickel phthalocyanine; (5) as in (1a) except that magnesium oxide is used as the metal yielding reagent the producer being magnesium phthalocyanine, instead of sodium sulphate ammonium sulphate or magnesium sulphate may be used and when magnesium sulphate is used the magnesium oxide may be omitted and the amount of magnesium sulphate increased by an amount equivalent to the magnesium contained in the magnesium oxide; (6), (7) and (8) as in (1a) except that sulphuric acid, sodium sulphamate and diethyl sulphate respectively are used as promoters instead of sodium sulphate.  Instead of diethyl sulphate in (8) there may be used the sodium, calcium or ammonium salt of ethyl sulphuric acid. It is stated that neutral as well as acid sulphates of sodium, potassium, ammonium and of calcium, barium and strontium may be used as may also the sulphates of phthalocyanine-forming metals such as copper, aluminium, iron, nickel, cobalt, zinc, tin, magnesium and vanadium.  Other metal donors specified are metallic copper, and other copper salts instead of aqueous chloride, aluminium acetate, magnesium nitrate or chloride, nickel nitrate, cobalt metallic zinc or its salts, iron or iron salts, tin or its salts and vanodyl salts.  Other phthalocyanine intermediates specified are o-dicarboxylic acid chlorides, e.g. phthalyl chloride, and o ,o \sv-polychloro or -polybromo-o-dimethyl aromatic compounds (e.g. o -tetra-, -penta-, or -hexachloro-o-xylene), and o -chloro- or -bromo-o-methyl aromatic nitriles, e.g. o -mono-, di- or -tri-chloro-o-tolunitrile.  U.S.A. Specification 2,214,477 is referred to.